qemu: error out on USB ports out of range

My overly sophisticated address reservation code forgot
to add an error message for user-requested ports out of range.

https://bugzilla.redhat.com/show_bug.cgi?id=1399260

src/conf/domain_addr.c

@@ -1987,6 +1987,13 @@ virDomainUSBAddressReserve(virDomainDeviceInfoPtr info,
                                                   portStr)))
         goto cleanup;
 
+    if (targetPort >= virBitmapSize(targetHub->portmap)) {
+        virReportError(VIR_ERR_XML_ERROR,
+                       _("requested USB port %s not present on USB bus %u"),
+                       portStr, info->addr.usb.bus);
+        goto cleanup;
+    }
+
     if (virBitmapIsBitSet(targetHub->portmap, targetPort)) {
         virReportError(VIR_ERR_XML_ERROR,
                        _("Duplicate USB address bus %u port %s"),

tests/qemuxml2argvdata/qemuxml2argv-usb-ports-out-of-range.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219136</memory>
+  <currentMemory unit='KiB'>219136</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <controller type='usb' index='0'/>
+    <memballoon model='virtio'/>
+    <hub type='usb'>
+      <address type='usb' bus='0' port='1'/>
+    </hub>
+    <input type='mouse' bus='usb'>
+      <address type='usb' bus='0' port='4'/>
+    </input>
+    <hub type='usb'>
+      <address type='usb' bus='0' port='1.9'/>
+    </hub>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1320,6 +1320,9 @@ mymain(void)
     DO_TEST("usb-ports",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_USB_HUB,
             QEMU_CAPS_NODEFCONFIG);
+    DO_TEST_PARSE_ERROR("usb-ports-out-of-range",
+            QEMU_CAPS_CHARDEV, QEMU_CAPS_USB_HUB,
+            QEMU_CAPS_NODEFCONFIG);
     DO_TEST("usb-port-autoassign",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_USB_HUB,
             QEMU_CAPS_NODEFCONFIG);